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US4047919A - Apparatus for press bending relatively thin glass sheets - Google Patents

Apparatus for press bending relatively thin glass sheets Download PDF

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Publication number
US4047919A
US4047919A US05/589,020 US58902075A US4047919A US 4047919 A US4047919 A US 4047919A US 58902075 A US58902075 A US 58902075A US 4047919 A US4047919 A US 4047919A
Authority
US
United States
Prior art keywords
sheet
glass
bending
press member
sheets
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/589,020
Other languages
English (en)
Inventor
Waldemar W. Oelke
Floyd T. Hagedorn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pilkington North America Inc
Original Assignee
Libbey Owens Ford Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Libbey Owens Ford Co filed Critical Libbey Owens Ford Co
Priority to US05/589,020 priority Critical patent/US4047919A/en
Priority to AR263696A priority patent/AR207195A1/es
Priority to CA254,298A priority patent/CA1072336A/en
Priority to ZA763433A priority patent/ZA763433B/xx
Priority to GB24134/76A priority patent/GB1512494A/en
Priority to AU14833/76A priority patent/AU497927B2/en
Priority to BE168093A priority patent/BE843146A/xx
Priority to FI761782A priority patent/FI59976C/fi
Priority to BR7603958A priority patent/BR7603958A/pt
Priority to LU75209A priority patent/LU75209A1/xx
Priority to ES449076A priority patent/ES449076A1/es
Priority to NL7606770A priority patent/NL7606770A/xx
Priority to FR7619006A priority patent/FR2315486A1/fr
Priority to NZ181242A priority patent/NZ181242A/xx
Priority to SE7607132A priority patent/SE420194B/xx
Priority to MX76100384U priority patent/MX3632E/es
Priority to IT50078/76A priority patent/IT1061579B/it
Priority to DE19762628518 priority patent/DE2628518A1/de
Application granted granted Critical
Publication of US4047919A publication Critical patent/US4047919A/en
Assigned to LOF GLASS, INC. reassignment LOF GLASS, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: LIBBEY-OWENS-FORD COMPANY AN OH. CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B27/00—Tempering or quenching glass products
    • C03B27/04—Tempering or quenching glass products using gas
    • C03B27/044—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position
    • C03B27/0442—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position for bent glass sheets
    • C03B27/0445—Tempering or quenching glass products using gas for flat or bent glass sheets being in a horizontal position for bent glass sheets the quench unit being adapted to the bend of the sheet
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C03B23/023—Re-forming glass sheets by bending
    • C03B23/03—Re-forming glass sheets by bending by press-bending between shaping moulds
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2225/00—Transporting hot glass sheets during their manufacture
    • C03B2225/02—Means for positioning, aligning or orientating the sheets during their travel, e.g. stops

Definitions

  • the present invention relates generally to the production of curved, tempered sheets of glass and, more particularly, to an improved method of and apparatus for bending and heat treating relatively thin glass sheets.
  • Bent sheets of glass are commonly used as glazing closures in vehicles such as automobiles and the like.
  • the glass sheets must be bent to precisely defined curvatures dictated by the configurations and size of the openings and the overall styling of the vehicle.
  • bent glass sheets utilized as glazing closures in vehicles be tempered to increase their resistance to damage resulting from impact and, in the event of breakage, to fragment into relatively small harmless particles as opposed to the large, jagged, potentially dangerous pieces otherwise resulting from untempered glass sheets when broken.
  • the commercial production of curved, tempered sheets of glass for such purposes includes heating pretrimmed, flat sheets of glass to the softening temperatures thereof, bending the heated sheets to a desired curvature between a pair of complementary mold sections and then chilling the bent sheets in a controlled manner to a temperature below the annealing range of glass.
  • the above operations are carried out successively while the sheets of glass are being advanced substantially continuously along a fixed path to a heating area, a bending area, and a chilling or tempering area.
  • the temperature of the glass sheet must be above a predetermined minimum level so as to maintain the core or central portion thereof above a deformation temperature upon being exposed to the tempering medium.
  • the residual heat remaining in glass sheets of conventional thicknesses is generally above such predetermined minimum level after bending for immediate advancement to the tempering area and exposure to the tempering medium.
  • the heat initially imparted to the sheet to bring it to the proper bending temperature can also be utilized in the final heat treating tempering operation.
  • the thicknesses thereof preferably ranging from about 0.100 to 0.156 inch for example. While the process described above is admirably suited for the mass production of the thicker glass sheets, it does not lend itself to the processing of relatively thinner glass sheets because of the lesser ability of such thinner sheets to retain heat. As the thickness of the glass decreases, the rate of heat loss increases. Thus, the heat loss occurring between initial heating and tempering occasioned by the intermediate bending operation in accordance with the above technique brings the temperature of a thin glass sheet down to a level below the aforementioned minimum temperature at which satisfactory tempering can be effected.
  • FIG. 1 is a side elevational view of a bending and tempering apparatus constructed in accordance with this invention, with parts of the heating and tempering sections broken away;
  • FIG. 2 is a plan view, partly in section, on an enlarged scale, taken along line 2--2 of FIG. 1;
  • FIG. 3 is a plan view, on an enlarged scale, taken along the line 3--3 of FIG. 1;
  • FIG. 4 is a vertical sectional view, on an enlarged scale, taken along line 4--4 of FIG. 1;
  • FIG. 5 is a vertical sectional view, on an enlarged scale, taken along line 5--5 of FIG. 1.
  • FIG. 1 a glass sheet bending and tempering apparatus comprehensively designated 10, which includes a continuous conveyor system 11 adapted to support a plurality of sheets S in a generally horizontal plane for movement along a continuous, substantially horizontal path through a heating section 12 having a furnace 13 for heating the sheets to their softening point or bending temperature, a bending station 15 having means for bending the heated sheets S to the desired curvature, and a tempering section 16 having chilling means 17 for rapidly reducing the temperature of the bent sheets to produce the desired temper therein.
  • a continuous conveyor system 11 adapted to support a plurality of sheets S in a generally horizontal plane for movement along a continuous, substantially horizontal path through a heating section 12 having a furnace 13 for heating the sheets to their softening point or bending temperature, a bending station 15 having means for bending the heated sheets S to the desired curvature, and a tempering section 16 having chilling means 17 for rapidly reducing the temperature of the bent sheets to produce the desired temper therein.
  • the sheets are positioned on the conveyor system 11 in a manner orienting their respective long dimensions in the direction of travel i.e., normal to the axes of the conveyor rolls forming the system 11. Such an orientation positions the sheet, when subsequently bent to a complex shape, in the most favorable position for proper tempering as will hereinafter be more fully explained.
  • the glass sheets are heated in the furnace 13 which is of the tunnel-type having side walls 18, a top wall 20 and a bottom wall 21 defining a heating chamber 22.
  • the heating chamber 22 can be heated in any desired manner by suitable heating means, such as gas burners or electrical resistance elements for example (not shown), located at the top and side walls of the furnace 13.
  • suitable heating means such as gas burners or electrical resistance elements for example (not shown) located at the top and side walls of the furnace 13.
  • Such heating means are suitably controlled by apparatus (also not shown) to obtain the desired temperature at various points in the heating chamber 22.
  • the sheets S are carried through the heating chamber 22 of the furnace on a plurality of conveyor rolls 23, forming part of the conveyor system 11, and extending transversely across the chamber 22 with their opposite ends projecting through the opposite side walls 18 and suitably journalled in bearing blocks (not shown) located exteriorly of and along the side walls 18 of the furnace.
  • a plurality of glass sheets are individually loaded on and supported in a generally horizontal plane on the longitudinally spaced conveyor rolls 23 at the entrance end of the furnace (not shown) and heated substantially uniformly in a controlled manner to the desired bending temperature during their passage therethrough.
  • the heated glass sheets S are transferred from conveyor rolls 23 onto a second series of spaced conveyor rolls 26, also part of the conveying system 11 and which are interposed between the heating and bending stations.
  • the sheets S are then transferred to a third series of spaced conveyor rolls 27, which support the glass sheets S horizontally for movement into and within the bending station 15 between a pair of complementary bending press members, hereinafter described, before and after bending, and then convey them to the tempering station 16.
  • the bending means comprises an upper male press member 30 and a lower female press member 31 having opposed complemental shaping surfaces conforming to the desired curvature of the sheet to be bent.
  • the press members 30 and 31 are mounted for relative movement toward and away from each other on a structural frame 32, which includes a framework of vertically disposed columns 33 and horizontally extending beams 35 interconnected and tied together to form a rigid, box-like structure.
  • a base member 36 extends between the upright columns 33 for supporting the female press member 31 and associated parts.
  • the male press member 30 is mounted above conveyor rolls 27 for vertical reciprocal movement relative to frame 32 while the female press member 31 is located below the conveyor rolls 27 and mounted for vertical reciprocal movement toward and away from the male press member 30.
  • a pair of laterally spaced locator stops 37 are positioned in the path of movement of the advancing glass sheets to interrupt movement thereof and accurately position the same in the desired location relative to the press members 30 and 31.
  • Each stop 37 is secured to the distal end of a piston rod 38 of a fluid actuating cylinder 40 mounted on a carriage 41.
  • the cylinders 40 are operative to raise and lower the stops 37 between an upper position above conveyor rolls 27 in the path of movement of the glass sheets S and a lower position therebeneath.
  • the male press member 30 is of outline or ring-type construction and comprises a continuous shaping rail 42 connected to a base plate 43 by a plurality of connecting rod members 45.
  • the shaping rail 42 conforms in outline to the glass sheets S to be bent and is provided with a downwardly directed, generally convex shaping surface 46 on the lower surface thereof to impart the desired curvature to the sheet.
  • the particular outline of the shaping rail 42, as well as the specific curvature of the shaping surface 46 is dictated by the desired shape of the glass sheet being bent and can vary widely, as desired.
  • a protective covering 47 formed of a suitable refractory material, is rigidly secured to the lower face of base plate 43 to protect the latter from the severe temperatures generated in the press area, as will hereinafter be explained.
  • the means for supporting the male press member 30 on frame 32 includes a pair of actuating cylinders 48 (only one of which is shown in FIG. 1) mounted on the upper horizontal beams 35 and having suitable reciprocable pistons (not shown) provided with piston rods 49 connected at their outer ends to a vertically reciprocal platen frame 50.
  • the base member 43 of the male press member 30 is connected to the platen frame 50 for movement therewith by means of interconnected structural members 51 and 52 and a support plate 53 extending transversely of the platen frame 50.
  • a plurality of guide posts 55 are connected at their lower ends to the four corners of platen frame 50, respectively, and extend upwardly through suitable bushings 56 mounted on upper horizontal beams 35 for sliding movement relative thereto to properly guide platen frame 50 during its vertical reciprocal movement.
  • the female press member 31 is also of outline or ring-type construction and comprises a base plate 58 secured to the carriage 41 and a shaping rail 60 connected to the base plate 58 in spaced relation thereto via a series of connecting rods 61.
  • the shaping rail 60 conforms in outline to the glass sheets S to be bent and is provided on its upper face with a generally concave shaping surface 62 complementary to the male press member shaping surface 46 in opposed relation thereto.
  • the female rail 60 is formed of a plurality of segments (FIGS. 1 and 3) including end bars 63 extending substantially in the same direction as the conveyor roll axes and side bars 65 extending generally transversely of the conveyor rolls 27 and spaced apart from each other a sufficient distance to pass between adjacent rolls 27 when raised and lowered.
  • the carriage 41 is supported by a pair of guide members 66 (FIG. 1) and vertically movable by a fluid actuator 67 mounted on base member 36 and having a suitable piston rod 68 for raising and lowering the female press member 31 between its lower position beneath conveyor rolls 27 and its upper position thereabove for lifting a heated glass sheet S from the conveyor rolls 27 and pressing the same against the male press member 30 between the complemental shaping surfaces 46 and 62, thus forming the glass sheet into the desired curvature.
  • piston rod 68 is retracted to lower the female press member 31 below conveyor rolls 27, depositing the bent sheet thereon for advancement into the tempering section.
  • the temperature thereof when exposed to the chilling medium must be above a minimum level, approximately 1100° F. for example, to maintain the glass core at or above the deformation temperature.
  • a minimum level approximately 1100° F. for example, to maintain the glass core at or above the deformation temperature.
  • some heat loss will occur during the bending cycle as a result of the cooler ambient temperature of the bending area and the relatively cool bending equipment engaging the sheet.
  • initially heating the sheets to approximately 1130°-1165° F. will compensate for the heat losses occasioned by bending while maintaining the temperature above said minimum level for quality tempering.
  • the heat initially imparted to the sheets to bring them to the proper bending temperature can also be utilized in the final heat treating or tempering operation.
  • a significant feature of the present invention is the resolution of the above problem by providing means in the press members for reheating or applying supplemental heat to at least selective portions of the thin sheet after initial heating and immediately prior to the bending thereof.
  • This expedient makes up any heat loss occurring during conveyance of the thin sheet from the furnace to the press area and maintains the sheet, immediately prior to pressing, at an adequate temperature, without overheating, to compensate for heat losses occurring during the bending cycle and thereby assure a proper glass temperature for quality tempering.
  • a plurality of heating elements in the form of gas-fired radiant burners, generally designated 70 are mounted on the press members 30 and 31.
  • the burners 70 are substantially identical and each comprises a head 71 having a dish-shaped internal wall and a conduit 72 threaded at one end into a socket 73 formed on its associated manifold and at the other end into the neck portion 75 of head 71.
  • the threaded connection between the burner head 71 and conduit 72 affords axial adjustment of the burner to vary the length thereof for spacing head 71 at an optimum distance from the sheet S to be bent.
  • a lock nut 76 is threaded onto conduit 72 in bearing engagement against neck portion 75 to secure the burner head 71 in the selective adjusted position.
  • the burners 70 are remotely controlled by an electrical control system (not shown) for controlling the pressure of the gas flowing therethrough between a low pressure or "pilot" setting and a high pressure setting for a purpose hereinafter explained.
  • Each conduit 72 is provided with a control valve 77 to individually vary the pressure setting thereof between the aforementioned low and high pressure settings and consequently the amount of gas admitted to its associated burner and the intensity of the heat generated thereby.
  • the burners 70 of the male press member 30 are connected to manifolds, identified by reference numerals 78a to 78d, in turn connected to a suitable source of combustible gas under pressure (not shown).
  • the burners 70 of the lower press member 31 (FIG. 3) are connected to a series of manifolds 80a through 80e, also connected to a suitable source of combustible gas under pressure.
  • These latter burners are arranged in rows extending generally parallel to the conveyor rolls 27, the rows being laterally spaced apart to provide clearance for the rolls 27 upon vertical movement of the lower press member 31.
  • Both sets of manifolds are supported against their respective base plates by suitable clamps 81. It should be appreciated that any suitable heating elements capable of generating and directing heat against the opposite glass surfaces can be used in lieu of those shown and described, if desired.
  • the conveyor rolls 27 in bending station 15 support the glass sheets S before and after bending and are specially configurated, as will hereinafter become apparent, to preserve the shape imparted to the glass sheets during bending.
  • the conveyor rolls 27 extend transversely of the path of movement of the sheets S in a laterally spaced relation and are mounted on rotatable shafts 79 journalled for rotation adjacent their respective opposite ends in suitable bearings (not shown).
  • Suitable drive means (not shown) connected to a suitable source of power is provided for rotating the shafts 79 and thereby conveyor rolls 27 in unison. Since such drive means are well known and, per se, form no part of the present invention, it is believed that no further description or amplification thereof is necessary.
  • the conveyor rolls 27 receive the sheets after bending and, as best shown in FIG. 4, preferably are shaped to fit the finished transverse curvature of the bent sheets.
  • Each conveyor roll 27 is formed of a suitable material and is provided with a pair of cylindrical end portions 82 and a central portion 83 having a progressively diminishing cross section from the end portions 82 inwardly toward the center thereof to provide curved, generally convex supporting surfaces 85 in front elevation complementary to the curvature of the heat-softened bent glass sheets.
  • These curved surfaces 85 offer support for the bent sheets while preserving the shape thereof by preventing the sagging of the sheets out of their desired shape during conveyance out of the bending area.
  • the rolls 27 can be covered with fiber glass, if desired, to protect the surfaces of the bent sheets.
  • the illustrative glass part shown in the drawings and fabricated in accordance with the present invention is one of the most difficult to form because of the complexity of its shape wherein it is bent about two intersecting axes.
  • the transverse curvature imparted to the sheet is effected about a line, hereinafter referred to as a "chord line” indicated by x--x in FIG. 3, which is offset from the true longitudinal axis of the sheet.
  • This chord line x--x defines a greater mass of glass on one side (upper side as viewed in FIG. 3) than the other side.
  • the length of the curved supporting surface 85 of each roll 27 is designed to be slightly shorter than the transverse dimension of the curved sheet at its widest dimension as shown in FIG. 4. This precludes engagement of the entire bottom surface of the sheet with such curved supporting surface 85. By avoiding frictional engagement of the lateral side portions adjacent the wider leading edge of the sheet with surfaces 85, which leading edge tends to steer or guide the advancing sheet, such "walking" is eliminated and a true longitudinal path of movement along the chord line is assured.
  • the complementary mold members 30 and 31 are shaped (FIG. 1) to impart a lengthwise curvature to the sheet S, particularly adjacent the trailing end thereof to form a swept-up tail end portion.
  • the first few rolls identified as 27a, 27b and 27c adjacent the entrance end of the bending station are disposed at varying vertical levels different from the remainder of the rolls 27.
  • Rolls 27a-27c are positioned at progressively lower levels to conjointly define a curved surface complementary to the curvature imparted to the corresponding tail end of the sheet S.
  • the relative vertical disposition of all the rolls can vary in conformity with the overall longitudinal shape imparted to the sheet S.
  • Conveyor rolls 86 are designed to adequately support the heat-softened bent sheets in a manner maintaining their shapes while permitting the maximum exposure of air thereto for rapid chilling.
  • each conveyor roll 86 comprises straight opposite end portions 87 (FIG. 5) having a common axis and a central, arcuately curved portion 88 contoured to fit the finished curvature of the bent sheets.
  • Each roll 86 comprises an inner, flexible, stationary core member 90 and an outer flexible, load carrying, rotatable sleeve 91 surrounding the core member 90. While the outer sleeve 91 is flexible for conforming to the curved shape of the inner core member 90, it is capable of transmitting torque without significant axial twist or distortion. Suitable means are provided for rotating the sleeves 91 in unison about core member 90 and their respective chordal axes. Since such drive means can be conventional and, per se, form no part of this invention, it is believed that a detailed description and illustration thereof is not necessary.
  • a sleeve 92 can be provided on the central curved portion 88 of each roll 86 to assure advancement of the bent sheet in a true linear path along its chord line.
  • the length of sleeve 92 is made shorter than the width of the sheet at its widest dimension to preclude engagement of the opposite sides of the sheet with the curved supporting surface of the roll and thereby avoid "walking" as described above.
  • specially configurated rolls identical to the rolls 27 employed in the press area can be used in lieu of the sleeved conveyor rolls 86, if desired.
  • the chilling means 17 in tempering station 16 comprise upper and lower blastheads 93 and 95 disposed above and below the path of movement of the glass sheets and are operable to direct opposed blasts of cooling fluid, such as air for example, toward and against the opposite surfaces of the sheets moving along such path.
  • Each of the blastheads 93 and 95 comprises a plurality of elongated manifolds 96 suitably secured to and communicating with a plenum chamber 97.
  • a plurality of tubes 98 project from the manifolds 96 inwardly toward the path of movement of the sheet S to direct a plurality of streams of cooling gases from a pressure supply source via plenum chambers 97 and manifolds 96 toward the opposite surfaces of the hot glass sheet.
  • the spacing of the tube outlets from the opposite surfaces of a hot, thin glass sheet is an important consideration in air quenching in producing sufficient quantities of cooling gases at the opposite surfaces of the thin sheets at pressures which will not adversely affect the finished product.
  • the optimum spacing for a particular tube size can be readily determined. Of course, this optimum spacing should extend throughout the entire surface areas of the sheet.
  • the tubes 98 of the illustrative embodiment depicted in FIG. 5 vary in length longitudinally of the respective manifold or transversely of the path of movement of the glass sheet to correspond to the curvature thereof.
  • the tubes 98 of the upper rows are lengthened from the opposite ends of their associated manifold progressively toward the center thereof while the tubes of the lower rows are shortened from the opposite ends of their associated manifold progressively toward the center of the row to accommodate concavely bent glass sheets therebetween. Because of the extreme curvature in the transverse direction of the sheet, it now becomes apparent why the specific sheet illustrated in the drawings is advanced on the conveyor system 11 in the direction of its longitudinal dimension. This permits optimum blasthead design to provide substantially equal spacing between the numerous tubes and the opposite surfaces of the sheet to achieve uniform tempering throughout. Such uniform tempering would not be possible if the sheet were transported in an orientation 90° from that shown in FIG. 5 because of the severe disparity in heights between the transverse marginal edges of the sheet and the center thereof and the attendant non-uniform spacing of the tube outlets therefrom.
  • a slidable gate 100 is located between the bending and the tempering stations 15 and 16.
  • the gate 100 is movable vertically between an open position shown in full lines and a closed position shown in dotted lines in FIG. 1 by means of an actuating cylinder 101 automatically operable to open the gate 100 just prior to the entry of a glass sheet into tempering station 16 and to close gate 100 immediately after the sheet is completely contained therein.
  • a flat glass sheet S is loaded onto the conveyor rolls 23 at the entrance end (not shown) on the furnace 13 for movement through the heating chamber 22 wherein the sheet is heated uniformly to substantially its softening point or bending temperature.
  • This heated sheet passes through the opening 25 and is transferred onto conveyor rolls 26 for movement into the bending station 15, wherein the sheet is transferred onto conveyor rolls 27 for movement between the male and female mold members 30 and 31.
  • a photoelectric cell or other suitable detection device actuates a control valve for increasing the pressure of the combustion gases delivered to the burners 70 from the lower pressure "pilot" setting to a high pressure setting. Since it is desirable to maintain the lower roll contacting surface of the sheet as cool as possible to minimize roll marking and distortion, preferably only the burners 70 of the male press member 30 are increased to this high pressure setting to direct the heat generated thereby against the upper surface only of the advancing sheet.
  • the burners of both press members can be increased to the high pressure setting or, only selective burners in the upper or both press members can be activated, as desired, to heat selective portions of the sheet.
  • this high pressure setting can vary with individual burners 70 as determined by manipulation of the hand-operable control valve 77.
  • supplemental heat is applied to the sheet as it advances between the press members 30 and 31 to assure the minimal temperature necessary for proper tempering without overheating.
  • This high pressure setting is maintained until the advancing sheet is halted by the stops 37, whereupon the high pressure setting is decreased to the lower pressure pilot setting.
  • the stops 37 which are longitudinally offset from each other, are effective to accurately align the sheet S between the opposed press members 30 and 31.
  • the aforementioned detection device responsive to the sheet entering the bending station 15, also initiates actuation of a timer (not shown) controlling operation of the bending cycle.
  • the timing of this control is such that when the leading edge of the sheet S engages the stops 37, cylinder 67 is actuated to raise the female press member 31 upwardly to remove the sheet from the conveyor rolls 27 and press the same against the male press member 30 to bend sheet S to the desired shape.
  • cylinders 40 are actuated to retract the locator stops 37 to permit advancement of the bent sheet when subsequently returned to the conveyor rolls 27.
  • the female press member is lowered below conveyor rolls 27 to deposit the bent sheet thereon.
  • the specially configurated rolls 27 receive the bent sheet and preserve the shape imparted thereto while advancing the same out of the bending station 15 and onto the successive contoured supporting surfaces of conveyor rolls 86.
  • cylinder 101 becomes operative by a suitable sensing device to retract and open gate 100 permitting entry of the sheet into tempering station 16.
  • the bent sheet is advanced on conveyor rolls 86 between the opposed tubes 98 of blastheads 93 and 95 at a speed promoting a suitable rate of cooling to obtain a quality temper in the sheet.
  • the preferred process according to this invention has been tested in a continuous production operation for successfully bending glass sheets to the desired curvature and satisfactorily tempering the same to meet particle size requirements when broken.
  • the glass sheets formed by this process were of a generally polygonal shape in plan having a thickness of approximately 0.125 inch, was approximately 30 inches in length along the longest edge thereof and about 29.5 inches in length along the slightly shorter opposite longitudinal edge. The sheet was 14 inches wide along the leading edge at its widest dimension and 3.5 inches wide at the narrow end.
  • the glass sheets were bent about a longitudinal line to form a transverse curve having a rise of approximately five-eighths of an inch of the lateral marginal edges with respect to the center portion and the rear end portion was bent about a transverse line to form a swept-up trailing edge projecting about a half inch from the major portion or body of the sheet.
  • the low pressure or pilot setting for each burner was approximately 3 inches of water column and the high pressure setting was adjusted to about 15 inches water column.
  • the high pressure setting began as the leading edge of the advancing sheet, was disposed in vertical registry with the trailing or narrow end of the female press member 31 and was interrupted when the leading edge engaged stops 37.
  • the bent sheets were rapidly chilled, using air at pressures of approximately 25 inches of water column against the top surfaces and 40 inches against the bottom surfaces.
  • the reason for the relatively greater bottom pressures which is the opposite of conventional air tempering practices, was to aid in developing and freezing the cooler bottom "skin" of the sheet.
  • the relatively higher bottom pressures prevented the swept-up tail end from curling downwardly out of the desired shape and tended to enhance optical quality.
  • the lesser top pressures prevented the bent sheets from being pressed against the conveyor rolls, thus minimizing roll distortion.
  • the sheets were not "floating" on the rolls because the higher bottom pressure was somewhat balanced by the greater volume of air from the upper blasthead, which was designed to carry more tubes than the lower blasthead.
  • An improved method and apparatus for bending and tempering relatively thin glass sheets having compound bends by reheating or applying supplemental heat to the sheets immediately prior to bending to make up heat losses occurring after initial heating and thereby maintain the temperature of the glass within acceptable limits for quality tempering.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
US05/589,020 1973-06-23 1975-06-23 Apparatus for press bending relatively thin glass sheets Expired - Lifetime US4047919A (en)

Priority Applications (18)

Application Number Priority Date Filing Date Title
US05/589,020 US4047919A (en) 1975-06-23 1975-06-23 Apparatus for press bending relatively thin glass sheets
AR263696A AR207195A1 (es) 1975-06-23 1976-01-01 Metodo de curvar y tratar termicamente laminas de vidrio delgadas
CA254,298A CA1072336A (en) 1975-06-23 1976-06-08 Method of and apparatus for bending relatively thin glass sheets
ZA763433A ZA763433B (en) 1975-06-23 1976-06-09 Method of an apparatus for bending relatively thin glass sheets
GB24134/76A GB1512494A (en) 1975-06-23 1976-06-10 Method of and apparatus for bending thin glass sheets
AU14833/76A AU497927B2 (en) 1973-06-23 1976-06-11 Method of and apparatus for binding relatively thin glass sheets
FI761782A FI59976C (fi) 1975-06-23 1976-06-18 Foerfarande och anordning foer boejning och vaermebehandling av relativt tunna glasskivor
BR7603958A BR7603958A (pt) 1975-06-23 1976-06-18 Processo e aparelho para curvatura e tempera de folhas de vidro finas
BE168093A BE843146A (fr) 1975-06-23 1976-06-18 Procede et appareil de cambrage et de traitement thermique de feuillesde verre relativement minces
ES449076A ES449076A1 (es) 1975-06-23 1976-06-21 Metodo y aparato para doblar y termotratar hojas de vidrio relativamente finas.
LU75209A LU75209A1 (xx) 1975-06-23 1976-06-21
FR7619006A FR2315486A1 (fr) 1975-06-23 1976-06-22 Procede et appareil de cambrage et de traitement thermique de feuilles de verre relativement minces
NZ181242A NZ181242A (en) 1975-06-23 1976-06-22 Bending thin glass sheets:reheating just before bending
SE7607132A SE420194B (sv) 1975-06-23 1976-06-22 Sett och anordning for att boja och vermebehandla relativt tunna glasskivor
MX76100384U MX3632E (es) 1975-06-23 1976-06-22 Mejoras en metodo y aparato para doblar y tratar termicamente hojas de vidrio relativamente delgadas
NL7606770A NL7606770A (nl) 1975-06-23 1976-06-22 Werkwijze en inrichting voor het buigen en met warmte behandelen van betrekkelijk dunne glazen platen.
IT50078/76A IT1061579B (it) 1975-06-23 1976-06-22 Perfezionamento nei procedimenti e dispositivi per la produzione di lastre di vetro curve
DE19762628518 DE2628518A1 (de) 1975-06-23 1976-06-23 Verfahren und vorrichtung zur herstellung gebogener, vergueteter glasscheiben, insbesondere duenner glasscheiben

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US05/589,020 US4047919A (en) 1975-06-23 1975-06-23 Apparatus for press bending relatively thin glass sheets

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AR (1) AR207195A1 (xx)
AU (1) AU497927B2 (xx)
BE (1) BE843146A (xx)
BR (1) BR7603958A (xx)
CA (1) CA1072336A (xx)
DE (1) DE2628518A1 (xx)
ES (1) ES449076A1 (xx)
FI (1) FI59976C (xx)
FR (1) FR2315486A1 (xx)
GB (1) GB1512494A (xx)
IT (1) IT1061579B (xx)
LU (1) LU75209A1 (xx)
MX (1) MX3632E (xx)
NL (1) NL7606770A (xx)
NZ (1) NZ181242A (xx)
SE (1) SE420194B (xx)
ZA (1) ZA763433B (xx)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4185983A (en) * 1978-11-01 1980-01-29 Ppg Industries, Inc. Method and apparatus for protecting tong-suspended glass sheets from buffeting
DE2942724A1 (de) * 1978-10-25 1980-04-30 Ppg Industries Inc Verfahren zur thermischen behandlung von glastafeln
US4218232A (en) * 1979-01-18 1980-08-19 Ppg Industries, Inc. Method of shaping moving sheets on roll forming apparatus
WO1989000539A1 (en) * 1987-07-10 1989-01-26 Libbey-Owens-Ford Co. Conveyor roll construction
US5346526A (en) * 1992-01-08 1994-09-13 Libbey-Owens-Ford Co. Apparatus for bending glass sheets
US5669954A (en) * 1994-06-20 1997-09-23 Gas Research Institute Forced convection heating apparatus and process for heating glass sheets therewithin
US5672191A (en) * 1994-06-20 1997-09-30 Gas Research Institute Forced convection heating apparatus and process for heating glass sheets therewithin
US5743931A (en) * 1995-08-14 1998-04-28 Libbey-Owens-Ford Co. Glass sheet conveying and bending apparatus
US5746799A (en) * 1994-06-20 1998-05-05 Gas Research Institute Process for heating glass sheets within a forced convection heating apparatus by mixing and distributing spent working fluid and combustion gases
US6045358A (en) * 1996-01-19 2000-04-04 Glasstech, Inc. Forced convection heating apparatus and process for heating glass sheets therewithin
EP1380548A1 (fr) * 2002-07-09 2004-01-14 G.M.C. For Glass Industry Pour l'industrie du Verre Machine de pressage-cintrage de feuilles de verre
FR2842186A1 (fr) * 2002-07-09 2004-01-16 Gmc For Glass Industry Pour L Machine de pressage-cintrage de feuilles de verre
WO2023055802A1 (en) * 2021-09-28 2023-04-06 Moore Nanotechnology Systems, LLC Molding apparatus and molding method for precision glass elements

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2516072A1 (fr) * 1981-11-12 1983-05-13 Ppg Industries Inc Moules refractaires pour la mise en forme de feuilles de verre
US4571253A (en) * 1984-07-26 1986-02-18 Libbey-Owens-Ford Company Press bending apparatus
DE4026094A1 (de) * 1990-08-17 1992-02-20 Ver Glaswerke Gmbh Verfahren und vorrichtung zum herstellen gebogener glasscheiben mit bereichen staerkerer biegung

Citations (4)

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US3333934A (en) * 1964-02-03 1967-08-01 Pittsburgh Plate Glass Co Method of and apparatus for shaping glass sheets with opposed pressing members
US3421875A (en) * 1965-09-13 1969-01-14 Libbey Owens Ford Glass Co Apparatus for bending glass sheets
US3607200A (en) * 1967-12-18 1971-09-21 Permaglass Apparatus for conveying glass sheets through adjacent bending and tempering stations
US3881906A (en) * 1973-08-20 1975-05-06 Libbey Owens Ford Co Heat treating glass sheets

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3338695A (en) * 1962-09-14 1967-08-29 Libbey Owens Ford Glass Co Method and apparatus for press bending and tempering glass sheets
US3396000A (en) * 1964-08-28 1968-08-06 Libbey Owens Ford Glass Co Method of and apparatus for bending and tempering glass sheets by differential heating
US3372016A (en) * 1966-07-07 1968-03-05 Libbey Owens Ford Glass Co Method for tempering and conveying glass sheets
US3573889A (en) * 1969-06-16 1971-04-06 Permaglass Method for shaping,tempering and laminating glass sheets
US3960535A (en) * 1974-09-13 1976-06-01 Libbey-Owens-Ford Company Method of and apparatus for bending glass sheets

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3333934A (en) * 1964-02-03 1967-08-01 Pittsburgh Plate Glass Co Method of and apparatus for shaping glass sheets with opposed pressing members
US3421875A (en) * 1965-09-13 1969-01-14 Libbey Owens Ford Glass Co Apparatus for bending glass sheets
US3607200A (en) * 1967-12-18 1971-09-21 Permaglass Apparatus for conveying glass sheets through adjacent bending and tempering stations
US3881906A (en) * 1973-08-20 1975-05-06 Libbey Owens Ford Co Heat treating glass sheets

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2942724A1 (de) * 1978-10-25 1980-04-30 Ppg Industries Inc Verfahren zur thermischen behandlung von glastafeln
US4185983A (en) * 1978-11-01 1980-01-29 Ppg Industries, Inc. Method and apparatus for protecting tong-suspended glass sheets from buffeting
US4218232A (en) * 1979-01-18 1980-08-19 Ppg Industries, Inc. Method of shaping moving sheets on roll forming apparatus
WO1989000539A1 (en) * 1987-07-10 1989-01-26 Libbey-Owens-Ford Co. Conveyor roll construction
US5346526A (en) * 1992-01-08 1994-09-13 Libbey-Owens-Ford Co. Apparatus for bending glass sheets
AU661536B2 (en) * 1992-01-08 1995-07-27 Libbey-Owens-Ford Co. Method and apparatus for bending glass sheets
US5735924A (en) * 1994-06-20 1998-04-07 Gas Research Institute Process for heating glass sheets therewithin a forced convection heating apparatus by controlling impingement velocity
US5672191A (en) * 1994-06-20 1997-09-30 Gas Research Institute Forced convection heating apparatus and process for heating glass sheets therewithin
US5669954A (en) * 1994-06-20 1997-09-23 Gas Research Institute Forced convection heating apparatus and process for heating glass sheets therewithin
US5746799A (en) * 1994-06-20 1998-05-05 Gas Research Institute Process for heating glass sheets within a forced convection heating apparatus by mixing and distributing spent working fluid and combustion gases
US5762677A (en) * 1994-06-20 1998-06-09 Gas Research Institute Process for heating glass sheets within a forced convection heating apparatus by controlling temperature
US5792232A (en) * 1994-06-20 1998-08-11 Gas Research Institute Forced convection heating apparatus
US5743931A (en) * 1995-08-14 1998-04-28 Libbey-Owens-Ford Co. Glass sheet conveying and bending apparatus
US6045358A (en) * 1996-01-19 2000-04-04 Glasstech, Inc. Forced convection heating apparatus and process for heating glass sheets therewithin
EP1380548A1 (fr) * 2002-07-09 2004-01-14 G.M.C. For Glass Industry Pour l'industrie du Verre Machine de pressage-cintrage de feuilles de verre
FR2842184A1 (fr) * 2002-07-09 2004-01-16 Gmc For Glass Industry Pour L Machine de pressage-cintrage de feuilles de verre
FR2842186A1 (fr) * 2002-07-09 2004-01-16 Gmc For Glass Industry Pour L Machine de pressage-cintrage de feuilles de verre
WO2023055802A1 (en) * 2021-09-28 2023-04-06 Moore Nanotechnology Systems, LLC Molding apparatus and molding method for precision glass elements

Also Published As

Publication number Publication date
MX3632E (es) 1981-04-07
SE7607132L (sv) 1976-12-24
LU75209A1 (xx) 1977-02-17
ES449076A1 (es) 1977-07-01
IT1061579B (it) 1983-04-30
GB1512494A (en) 1978-06-01
BR7603958A (pt) 1977-03-22
SE420194B (sv) 1981-09-21
CA1072336A (en) 1980-02-26
FI59976C (fi) 1981-11-10
AU497927B2 (en) 1979-01-25
BE843146A (fr) 1976-10-18
AR207195A1 (es) 1976-09-15
DE2628518A1 (de) 1977-01-20
FR2315486B1 (xx) 1980-08-08
FI59976B (fi) 1981-07-31
ZA763433B (en) 1977-05-25
AU1483376A (en) 1977-12-15
FR2315486A1 (fr) 1977-01-21
NL7606770A (nl) 1976-12-27
NZ181242A (en) 1978-09-20
FI761782A (xx) 1976-12-24

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Owner name: LOF GLASS, INC., 811 MADISON AVE., TOLEDO, OH 4369

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. SUBJECT TO CONDITION RECITED.;ASSIGNOR:LIBBEY-OWENS-FORD COMPANY AN OH. CORP.;REEL/FRAME:004687/0980

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Effective date: 19860320